Method and Configuration for Storing and Playing Back TV Transmissions

ABSTRACT

An improved method and configuration for operating a network containing a personal video recorder server having measures for receiving several digitally encoded TV channels, for feeding several terminals and for recording storable TV programs. The terminals have measures for selecting storable TV programs and measures for transmitting the choice to the PVR server. The configuration contains a first database in which the index of TV programs stored by the PVR in response to the selection produced by the terminal is recorded. The first database controls authorization or refusal to play back the stored programs on the terminal. A second database stores, for the first terminal, the other terminals authorized to play back the TV programs selected by the user of the first terminal or all TV programs associated therewith by the first data base index. Terminals that are not contained in the second database are not authorized.

The present invention relates to a method and a configuration for storing and playing back TV transmissions. In particular, the present invention provides an improved method and an improved configuration for operating a network PVR.

After tape-based analog video recording devices have for decades represented the only possible way for home users of recording and conveniently preserving transmissions broadcast by way of antenna, cable or satellite television, since fast and at the same time inexpensive video processors and powerful video codecs such as MPEG2 (1994) and MPEG4 (1998) have become available there has existed for several years a series of largely hard-disk based digital devices which offer a series of convenience functions alongside pure video recording.

This new generation of devices is often referred to as personal video recorder (PVR), sometimes also as digital video recorder (DVR). While these modern devices can naturally also be used as classic devices for the simple recording and subsequent playback of transmissions, their capabilities extend far beyond that level. A frequently used feature of a PVR is for example so-called time-shifted television, in which the user actually begins to play back a transmission while the recording is still running. Thanks to the powerful hardware of a modern PVR, the picture quality achieved in this situation is better than that of a conventional VHS or SVHS tape device.

Time-shifted television also enables the user to “pause” a transmission viewed live initially, to take a telephone call perhaps, and to continue the playback later, whereby it would appear to the user as if he had actually paused the live broadcast and continued it later. In the background, however, the user pressing the “Pause” button has caused his PVR to record the running transmission, and pressing the “Pause” button again results in the recorded transmission on the one hand continuing to be recorded and on the other already being played back.

The capability of a PVR which allows the user to skip large sections in a recording with minimum delay also enjoys great popularity. This is frequently used during playback to skip blocks of advertising contained in the recording. A series of services has established itself around this capability which facilitate the location of the limits of the advertising blocks, for instance by storing the beginning and the end of an advertising block as points in time relative to the beginning of a transmission as an index for the recording and thus enabling the advertising to be skipped automatically during the playback.

In addition to specially adapted consumer electronics devices, multimedia PCs with suitable software (known as home theater PC, HTPC) are also increasingly being used as PVRs. Technically, there is little difference between a special PVR and a PCPVR; both have a large (hard-disk) storage facility, adequate processor power and suitable video codecs.

Thanks to configurable software or firmware, both platform variants are in a position to offer the user further functions, such as searching for transmissions which fit thematically with his favorite transmissions. Common to both platform variants is the fact that the recording takes place locally with respect to the user and the quantity of transmissions that can be recorded is limited by the local disk storage unit. It is therefore often possible to transfer recorded transmissions from the internal memory of the device onto writable media such as (re-)writable CDs or DVDs. There is some effort involved in this however and, not least, the price of a PVR is also considerable. Furthermore, PVRs also suffer from the problem that a plurality of PVRs are additionally required in order to allow parallel recording of multiple transmissions. Expensive multituner devices only solve this problem to a limited extent because it will always be the case that fewer tuners are present than TV stations and moreover that the hardware of the PVR—sufficiently powerful for one channel—is reaching its limits with regard to the parallel recording of multiple channels.

In order to be able to offer users all the advantages of a PVR without them needing to invest in a PVR, a network PVR was proposed in the white paper “Network PVR: Everything an Demand”, Jay Schiller, nCube Corporation, available on the Internet at http://www.ncube.com/pressroom/downloads/nvpr-whitepaper.pdf, in which memory, coding logic and codecs are made available by a provider on the cable network. The user receives a device which allows him to select transmissions to store and to retrieve stored transmissions which are then transferred by means of a wideband connection in real time to the user. When compared with a PVR or an HTPC, such a device can be considerably less powerful. At the same time, the user can lease storage space practically without limit on the central PVR server while the operator of the PVR server only needs to provide one copy of each transmission which is then distributed when required to those users who have placed this transmission in their (virtual) memory.

In a development, such a network PVR can be implemented such that “programming” of the network PVR by the user is not required and the user instead has access to all the transmissions in his program assortment from approximately the most recent 4 weeks.

With regard to solutions which require a programming operation, perhaps because rights owners have not agreed to the blanket storage of the entire program for all users, it is however disadvantageous that only users who have programmed a transmission can subsequently also retrieve and play this back. The exchange of transmissions, realized in the case of tape devices by swapping cassettes and in the case of the expensive hard-disk PVR by swapping CDs or DVDs, is not possible with the network PVR because the user's content is stored on the network.

An object of the invention is therefore to set down a method and a configuration for storing and playing back TV transmissions, which avoids this disadvantage.

This object is achieved by a configuration for storing and playing back TV transmissions, which comprises the following:

-   -   a PVR server with means for receiving a plurality of digitally         coded TV channels, means for feeding a plurality of terminals         and means for recording TV transmissions to be stored;     -   at least one terminal with means for selecting TV transmissions         to be stored and means for transferring the selection to the PVR         server;         whereby the following are additionally provided:     -   a first database in which is stored for each terminal an index         of the TV transmissions stored by the PVR server in response to         a selection made at this terminal, whereby the first database         controls the granting or denial of permission to play back         stored transmissions on the terminals; and     -   a second database in which are noted for a first terminal         further terminals which are authorized to play back TV         transmissions selected by a user of the first terminal or all TV         transmissions associated with the first terminal through the         index of the first database, whereby terminals not noted in the         second database do not have this authorization.

The invention also relates to a method for storing and playing back TV transmissions, comprising the following steps:

-   -   reception of a plurality of digitally coded TV channels by a PVR         server which feeds a plurality of terminals and records TV         transmissions to be stored;     -   selection of TV transmissions to be stored by a terminal and         transfer of the selection to the PVR server;     -   storage in a first database of an index for each terminal of the         TV transmissions stored by the PVR server in response to a         selection made at this terminal, whereby the first database         controls the granting or denial of permission to play back         stored transmissions on the terminals; and     -   noting of further terminals for a first terminal in a second         database, whereby the further terminals are authorized to play         back TV transmissions selected by a user of the first terminal         or all TV transmissions associated with the first terminal         through the index of the first database and whereby terminals         not noted in the second database do not have this authorization.

Said problem is advantageously solved by the invention in that in addition to a first database, which manages the storage area assigned to a user of the network PVR, a second database is provided which for each terminal manages a list of further terminals that are authorized to play back transmissions which have been recorded on the first terminal at the request of a user. Any terminals not included in this list do not have this authorization.

Provision can advantageously be made to enable a user of the first terminal to edit the entries in the second database concerning a terminal. A user can thus for instance create a list of family members or friends who are permitted to access his content stored on the network PVR. In this situation, the maximum number of family members and friends that can be defined by a user can be restricted in accordance with copyright provisions, to 7 for instance. Provision can also be made to enable these family members and friends to only play back the content/TV transmissions but not to archive same.

The first database and the second database can advantageously be combined in a shared user database.

The present invention can advantageously also be used at a time when for legal or technical reasons the data occurring in the case of a recording is not stored in its entirety in a memory assigned to the network PVR but one part of the data to be stored with regard to the recording is sent to a memory of the selecting terminal. This can be necessary if an intro function without a network connection is to be enabled for the user, or if rights owners do not permit the creation of independently useable copies by operators of network PVRs. In the latter case the division of the data is performed in such a way that a small part of the data is stored in the terminal and the remaining, main part of the data, which is stored in the memory of the network PVR, does not actually result in any decodable content (picture and/or sound).

In order to enable users to exchange their recorded transmissions in this case as well, the local data assigned to a recording can be exchanged between the users either by way of the network or by means of data media. If data media are permitted, the second database then performs the function by way of example of monitoring and restricting the total number of copies produced.

Preferred embodiments of the present invention will be described in detail in the following with reference to a drawing.

The single FIGURE shows a configuration 100 with a network PVR or PVR server 102 and terminals 104A . . . 104N fed by the latter. The PVR server 102 receives digitally coded TV channels from an encoder 120. The encoder in turn receives the TV channels from a receiver 122 which receives suitable TV signals by way of a terrestrial antenna 124 and/or satellite antenna 126 and/or TV cable 128. In this situation, the encoder 120 and the receiver 122 can be constructed as one device. The encoder 120 utilizes a codec such as MPEG2 or MPEG4 for example or codecs derived from these in order to convey the TV signals which are initially present in analog form into an efficient digital data format. If a TV channel is already available as a digital data stream, for example as a digital video broadcast DVB (received terrestrially as DVB-T, via cable as DVB-C or via satellite as DVB-S), the encoder 120 can forward this data stream unmodified to the PVR server 102 or modify it before forwarding, for example by matching the bandwidth of the data stream to the bandwidth of the link to the terminals 104.

The PVR server is coupled to a mass storage device 108, for example to a hard disk drive array (HDD array). Numerous methods are known in the art for building redundant mass storage device arrays from hard disks, which are nevertheless still able to deliver the stored data in its entirety in the event of failure of individual hard disks. The use of such a redundant array, for example a redundant array comprising independent hard disks (RAID), is advantageous in conjunction with the present invention because a PVR server 102 and the attached mass storage device 108 stores all or at least a major part of the data for the TV recordings of numerous users.

The user terminals 104 are connected to the PVR server 102 for example by way of the TV cable network or a DSL link. Modern codecs permit an acceptable video quality with transfer rates upwards of a few hundred kbit/s. With the bandwidths of several Mbit/s that are technically possible over DSL links, two or more parallel video streams (for different playback devices in the user's household) or a single high-quality video stream are conceivable.

The terminals 104 are equipped with or coupled to local memory 110 which for example can be implemented as conventional hard disk and/or as flash memory and/or as RAM. Special forms such as mini hard drives available in flash memory card format are naturally also conceivable. In this situation, flash memory has the advantage that storage of data is possible independent of the presence of a supply voltage and at the same time particularly quiet terminals 104 are made possible because flash memory has no rotating or other mechanical parts.

In this situation, the memory 110 can be permanently coupled to the terminal 104 or can be configured as exchangeable. Lesser demands apply to the memory 110 of the terminals 104 than to the mass storage device 108 in respect of redundancy and failsafe behavior. Provision can be made as a convenience feature for the user which enables him to produce backup copies of the parts of the recordings stored in a case by case basis in his memory, for instance on a data medium (writable CD or DVD, external hard disk) not permanently situated in the terminal 104, using a network connection on a PC or also in a separate storage area offered by the PVR service provider (not shown). Furthermore, provision can be made to enable the user, in addition to these backup copies, to also create copies in order to forward the parts of the recordings stored on a case by case basis in his memory to other users, to friends for example.

With regard to the terminal or CPE 104, this can be a set-top box which is connected to a picture playback device 116. Alternatively, the terminal 104 can be integrated into the picture playback device 116. The picture playback device 116 can be a conventional television. Alternatively, it can also be a monitor which does not itself have a TV tuner. The terminal 104 has a user interface 106 which the user can use for example in order to manage his archive of recorded TV transmissions, manage the list of users that have access to his archive, etc. This user interface can, as is normal in the realm of set-top boxes, be implemented such that the user makes inputs using a remote control and sees outputs displayed on the picture playback device 116.

When the user of a first terminal 104A has selected a TV transmission, a data record identifying a TV transmission to be recorded is sent to the network-based PVR 102 (step 1) which uses a scheduler to make the TV transmission available for recording. A first database 130, a user database for example, manages the transmissions allotted for recording by a user and checks the user's authorizations, for instance as to whether the user has subscribed to the corresponding TV channel (step 2).

When a TV transmission is broadcast, in collaboration with the database 130 the PVR server 102 checks whether a user (a single user is sufficient) has allotted this transmission for recording (step 3). If this is the case, the recording is carried out (step 4). In this situation, the data occurring during the recording can be stored in its entirety in the memory 108 of the PVR server or divided into a local and a central part and stored accordingly in the memory 110 of the terminal 104 or in the mass storage device 108. If the transmission has been programmed for recording on a plurality of terminals 104 either a shared copy can be provided, which is stored completely or whose central part is stored in the memory 108 of the PVR server 102, or a separate copy is created for each terminal. Information for addressing the shared or the separate copy, a file name or other index information for instance, is subsequently stored in the first database 130 for each terminal which had the transmission allotted for recording. Such a user-related entry can contain further information in the form of metadata relating to the transmission, for instance an expiry date or the positions of possible advertising blocks, so as to allow the latter to be skipped.

If a division into central and local recording data occurs, the local data is accordingly sent to all the terminals 104 at which the transmission has been programmed for recording. In this situation, the division of the data can be performed such that at least the central data stream for its part no longer delivers a decodable video signal (picture and sound). Only when both data sets (from the memory 110 of a terminal 104 and from the mass storage device 108) are combined can the transmission be played back in its entirety.

A playback takes place when a user employs the user interface 106 at the terminal 104 to request the archive of available transmissions, which is sent from the database 130 to the terminal 104 for display by means of the user interface, for example on the screen 116. The user can select a recording from the archive and start the playback by means of an appropriate input. The terminal sends this request to the PVR server which uses the database 130 to locate the corresponding data in the memory 108 and send it as a video stream to the appropriate terminal 104.

If a division into central and local recording data has taken place, the parts of the recording stored in the memory 110 of the selecting terminal 104 and the parts stored in the mass storage device 108 can be combined in the PVR server 102. To this end, the data stored in the terminal is first transferred to the PVR server, where it is combined. The complete video data is then sent to the terminal 104 as a realtime data stream for playback.

Alternatively, the parts of the recording stored in the memory 110 of the selecting terminal 104 and the parts stored in the mass storage device 108 can be combined in real time in the terminal 104. In response to a user input the incomplete video data is sent by means of the PVR server 102 from the mass storage device 108 as a near-realtime data stream to the terminal 104, where it is supplemented by the data stored in the terminal 104 and played back. In this situation, near-realtime data stream means that depending on the type of division of data selected between local memory 110 and mass storage device 108 it is also possible for larger data sets to be situated in the local memory, intro sequences for instance, which are first played back before the data which may have been buffered until then is prepared for playback from the mass storage device 108.

A second database 132, which can also be implemented in a unified database jointly with the first database 130, stores for each user a list of further users who may either generally play back all transmissions recorded by this user or specifically those transmissions released by the user in question. To this end, a list containing authorized terminals 104B is maintained in the second database for each terminal 104A. Provided that an allocation of playback rights is also provided on the basis of individual transmissions, a data field to be filled by the user by means of the user interface 106 can be provided in the first database 130 for each transmission. With this data field it is possible to implement a positive list, in other words only transmissions with a corresponding entry in this data field are also made available to other users, or a negative list can be provided, in other words transmissions with a corresponding entry in this data field are not made available to other users. In this situation, provision can furthermore be made to make available a positive or negative list per entered authorized user so as to selectively make transmission accessible or not accessible only to individual users from the users noted in the list as being authorized in principle, in other words to also make available different transmissions from the user's archive to the different friends or family members.

If a user of a first terminal 104A has included a user of a second terminal 104B in the group of authorized users, for instance by means of corresponding inputs through his user interface 106A, provision can be made for the transmissions in the archive of the first user to also appear automatically in the archive of the second user, unless this has been excluded for individual transmissions in the case of allocation of playback rights on the basis of individual transmissions. In this situation, an identification marking can be provided, for example by means of color or menu design, which shows the second user that transmissions from the archive of the first user are involved. Alternatively, provision can be made whereby the first user must “send” a special transmission to the second user before it appears in the latter's archive. If a transmission appears in the archive of the second user, this can be played back by means of terminal 104B as if the transmission had been provided for recording by the second user (represented in summary by step 5).

If a division into central and local recording data has taken place, the parts of the recording stored in the memory 110A of the first user's terminal 104A originally selecting the transmission for recording and the parts stored in the mass storage device 108 can be combined in the PVR server 102. To this end, the data stored in the terminal 104A of the first user is first transferred to the PVR server 102, where it is combined. The complete video data is then sent to the playback terminal 104B of the second user as a realtime data stream for playback.

Alternatively, the parts of the recording stored in the memory 110A of the terminal 104A of the first user and the parts stored in the mass storage device 108 can be combined in real time in the playback terminal 104B of the second user. To this end, the local data concerning the transmission is transferred from the memory 110A to the memory 110B, and this is done either by means of the PVR server under the control of the databases 130 and 132, or by the first user passing a data medium containing this data to the second user.

The incomplete video data is then sent by means of the PVR server 102 from the mass storage device 108 as a near-realtime data stream to the 104B, where it is supplemented by the data now stored in the terminal 104B and played back.

In this situation, the database 132 can designed such that all the terminals 104N not flagged in the database 132 as authorized are not permitted to play back the recordings of a user in question. This can for example be implemented such that the transmissions of the terminal 104A are not contained in the archive data for the terminal 104N delivered from the database 130 in collaboration with the database 132.

As represented by the dashed line 140 a user group comprising the terminals 104A and 104B is formed in the manner described, whereby initially only the terminal 104B is authorized to access the transmissions of the terminal 104A, but not vice versa. Provision can be made to limit the number of users with whom any user is able to exchange transmissions, for instance in order to satisfy copyright requirements. For example, it is possible to specify that each user may make his transmissions available to a total of only seven further users who in turn are only permitted to view the transmissions of this user, whereby other uses are excluded, for instance copying to data media or storage in a permanent central archive.

If in the case of locally stored portions of the recording data the forwarding of said data is enabled, provision can be made for controlling the number and the type of copies that can be produced of these locally stored portions by way of the second database 132. For example, provision can be made whereby only seven copies to data media are permissible which can be used with a different terminal than the terminal used to produce the copies. The user can be forced by the action of the database 132 to precisely specify the terminals for which a special copy is to be useable, whereby use of the copy on other terminals remains unsuccessful.

This manner of forwarding transmissions can be combined with the described network-based forwarding of copies in that each forwarding of a transmission to a user in the user group decrements the number of copies that can be produced. The other way round, each copy produced can also prevent the forwarding to users in the user group, which can preferably be controlled by means of the positive list, in which no further entry can be created for a transmission which has already been forwarded as often as permitted using a data medium.

Alternatively, it is possible to provide only one of the two forwarding capabilities, in other words network-supported or using a data medium. In this situation, forwarding by means of a data medium is the more involved method for the user but it is functionally equivalent to what can be practiced with the recordings made by analog tape devices and is thus where necessary more consistent with the relevant applicable law. Network-supported forwarding on the other hand is an additional benefit for the user which, as a service feature, can on the one hand improve the competitive position of an operator of a network PVR and on the other hand can justify the imposition of special fees by the operator.

In a further alternative, provision can be made, for example, to send an e-mail from the first user to the second user, containing information, for instance in the form of a link which can be used at the terminal of the second user in order to play back a transmission referenced by this information. If the recording is present in its entirety in the memory 108 of the PVR server 102, the playback of the referenced transmission can take place immediately. If part of the data is stored in the terminal memory 110A of the first user however, this part of the data will either be embedded into the e-mail or retrieved from the terminal memory 110A of the first user before playback commences. 

1-12. (canceled)
 13. A configuration for storing and playing back TV transmissions, the configuration comprising: a plurality of user terminals; a personal video recorder server connected to said user terminals, said PVR server having means for receiving a plurality of digitally coded TV channels, means for feeding said user terminals and recording means for recording the TV transmissions to be stored; at least one of said user terminals having selecting means for selecting the TV transmissions to be stored and transferring means for transferring a selection to said PVR server; a first database coupled to said PVR server, said first database storing for each of said user terminals an index of the TV transmissions stored by said PVR server in response to a selection made at said one user terminal, said first database controlling a granting or denial of permission to play back stored transmissions on said plurality of user terminals; and a second database coupled to said PVR server, said second database storing for a first user terminal of said user terminals identification of further ones of said user terminals authorized to play back the TV transmissions selected by a user of said first user terminal or all the TV transmissions associated with said first user terminal through said index of said first database, said user terminals not stored in said second database do not have this authorization.
 14. The configuration according to claim 13, wherein entries in said second database concerning said first user terminal can be edited by the user of said first user terminal.
 15. The configuration according to claim 13, wherein said first database and said second database are combined in a shared user database.
 16. The configuration according to claim 13, further comprising a memory coupled to said one user terminal functioning as a selecting user terminal; further comprising a mass storage coupled to said PVR server; and wherein said recording means of said PVR server is configured such that a first part of data to be stored with regard to a recording is sent to said memory of said selecting user terminal and a second part of the data to be stored is stored in said mass storage device.
 17. The configuration according to claim 16, further comprising means for transferring a part of the data for a TV transmission stored in said first user terminal to an authorized one of said further user terminals, thereby enabling a playback of the TV transmission by said authorized further user terminals.
 18. The configuration according to claim 16, wherein said user terminals have copying means for copying a part of the data for a TV transmission stored in said first user terminal to a data medium which can be read in by said further user terminals, thereby enabling the playback of the TV transmission by said further user terminals, a number of copies created using said copying means is noted and restricted by said second database in addition to or instead of the authorizations for playing back TV transmissions.
 19. A method for storing and playing back TV transmissions, which comprises the steps of: receiving a plurality of digitally coded TV channels by a personal video recorder server, the PVR server feeding a plurality of user terminals and recording the TV transmissions to be stored; selecting the TV transmissions to be stored via a selecting user terminal of the user terminals and transferring a selection to the PVR server; storing in a first database an index, for each of the user terminals, of the TV transmissions stored by the PVR server in response to the selection made at the selecting user terminal, the first database controlling a granting or denial of permission to play back stored transmissions on the user terminals; and storing in a second database, identifications of further user terminals for a first user terminal of the user terminals, the further user terminals are authorized to play back the TV transmissions selected by a user of the first user terminal or all the TV transmissions associated with the first user terminal through the index of the first database and the user terminals not noted in the second database do not have this authorization.
 20. The method according to claim 19, which further comprises editing entries in the second database concerning a user terminal by a user of the first user terminal.
 21. The method according to claim 19, which further comprises combining the first database and the second database in a shared user database.
 22. The method according to claim 19, which further comprises with regard to a recording by the PVR server, sending a first part of data to be stored with regard to the recording to a memory of the selecting user terminal and storing a second part of the data to be stored in a mass storage device coupled to the PVR server.
 23. The method according to claim 22, which further comprises transferring a part of the data for the TV transmission stored in the first user terminal to the authorized further user terminals, thereby enabling a playback of the TV transmission by the authorized further user terminals.
 24. The method according to claim 23, which further comprises creating copies of a part of the data for the TV transmission stored in the first user terminal on a data medium by the user terminals, whereby the data medium can be read in by the further user terminals, thereby enabling the playback of the TV transmission by the further user terminals, whereby a number of copies created using a copying means is noted and restricted by the second database in addition to or instead of the authorizations for playing back TV transmissions. 